Documentation

A Layout1 value is a single plot area, with optional: axes on
each of the 4 sides; title at the top; legend at the bottom. It's
parameterised by the types of values to be plotted on the horizonal
and vertical axes.

Render several layouts with the same abscissa type stacked so that their
origins and axis titles are aligned horizontally with respect to each
other. The exterior margins and background are taken from the first
element.